Bio-implants often fail due to effects of bacterial diseases and/or insufficient integration of the medical device into the surrounding tissue. Typical medicinal and surgical treatment options are often inadequate with regard to preventing failure of these devices.
As one example, peri-implantitis is a disease characterized by progressive loss of bone surrounding dental implants which may occur years after successful implantation and normal osseointegration that promotes integration of the implant and surrounding bone tissue. The disease is initiated when bacteria carried by saliva colonize exposed surfaces of the implant forming a biofilm, which then initiates an inflammatory response in the host. When this initial infection spreads to affect the soft tissues immediately surrounding the implant the condition is referred to as peri-implant mucositis. Often the infection spreads further to affect the boney support around the implant. Bleeding or suppurating tissue surrounding an implant with concurrent bone loss is referred to as peri-implantitis. It is generally agreed that the bacteria responsible for peri-implantitis and peri-implant mucositis are drawn from the same population responsible for periodontal disease in natural teeth. In contrast, normal, well integrated implants are populated by the bacteria typical of healthy teeth. Peri-implantitis may affect patients many years after implant insertion.
As another example, periprosthetic infections can affect prosthetic limbs, for example, percutaneous osseointegrated prosthetic systems (PODS). PODS include prosthetic limbs attached via insertion of a portion of the prosthetic limb into the medullary canal of residual bone after a limb amputation. Periprosthetic infections may originate from the skin-implant interface. Additionally, an inadequate skin seal (e.g., lack of a stable epidermal protective later against bacteria), lack of epithelial-implant integration and subsequent downgrowth, sinus tract formation and immune responses to the presence of the implant can augment infection rates.